This week's Mississippi River bridge collapse has thrown the spotlight onto ageing US infrastructure, with experts warning that billions must be spent to bring standards into line.

The American Society of Civil Engineers warned in a report two years ago that between 2000 and 2003, more than 27% of the nation's almost 600,000 bridges were rated as structurally deficient or functionally obsolete.

"It will cost US$9.4 billion dollars a year for 20 years to eliminate all bridge deficiencies," the group says, adding that "long-term under-investment is compounded by the lack of a federal transportation program".

"America must change its transportation behaviour, increase transportation investment at all levels of government, and make use of the latest technology," the Report card for America's infrastructure adds.

The organisation estimates that US$1.6 trillion dollars are needed over five years to categorise US infrastructure as being in good condition.

"The only way to completely eliminate the risk is to not drive on bridges," he says, adding that this week's accident would probably renew calls for more modern technology to be used in maintaining bridge safety.

"There is incredible technology out there to help monitor and diagnose problems, and we continue to develop new technologies to keep up with the infrastructure of bridges," he says. "This will bring new focus to that."

This week's deadly bridge collapse came just two weeks after an ageing steam pipeline exploded in Manhattan, spewing hot vapour, mud and rock in the city's business district.

The explosion of the pipe, which was more than 80 years old, came as a stark reminder that much of the city's infrastructure is more than a century old.

New York also suffers from a creaking electrical grid that comes close to collapse when demand spikes during summer heat waves. Last year, tens of thousands were left without power for days on end.